Temperature measurements using nuclear magnetic resonance

Abstract

Publisher Summary Temperature-dependent nuclear magnetic resonance (NMR) parameters include spin lattice ( T 1 ) and spin-spin (T 2 ) relaxation times, chemical shifts, dipolar and scalar couplings, molecular diffusion coefficients, and net equilibrium polarization. Dependent upon the particular application, each of these parameters are utilized as an NMR 'thermometer.' This chapter describes in detail liquid-state NMR, solid-state NMR, and MRI, introducing their physical basis for the temperature dependence of the particular NMR parameter along with their applications. Although the emphasis is placed on chemical compounds, which have been used in actual temperature measurements, the chapter also briefly covers the thermal properties of compounds which may bear re-examination as temperature probes. The chapter briefly summarizes the basis for the temperature dependence of those NMR parameters most widely used for thermal measurements. The parameters considered are net polarization, chemical shielding ( σ ), T 1 relaxation times, scalar (J) coupling, and molecular diffusion coefficients. Intrinsic transition metal chemical shifts are discussed and the indirect effects on the chemical shift of protons in the ligand are described.